Johnson Controls P72AA-27 DPST Pressure Switch 100/400 PSI, 36" ,Open-Low

The Johnson Controls P72AA-27 DPST Pressure Switch is a safety device that is used to measure pressure in HVAC systems besides offering safety. This switch has a 36” capillary tube that measures pressure changes in your system and then provides an electrical on/off signal based on the set limits. The DPST design enables the switch to break two different circuits, which enhances its control and safety. On the other hand, the switch may be used to turn on equipment such as condenser fans each time the pressure rises above a high limit usually 400 PSI to enable proper functionality of the system.